The invention relates to an assembly tool for assembling a sealing ring in an annular groove of a machine part, in particular of a valve plate.
There are already known assembly tools in which the seal is press-fitted into the sealing groove by a hydraulic press. Such hydraulic presses are complicated and expensive to produce. Moreover, they are large and heavy and are accordingly not easy to transport. For this reason, the user typically procures only a single such device and installs it at some central point in a repair and maintenance facility. This in turn requires that the individual machine parts, such as valve plates, be brought to the central maintenance facility, so that the new sealing rings can be inserted there, in order for the seals to be refurbished.
From U.S. Pat. No. 4,550,486, a power tool is known that is intended to mounting a sealing ring in a tool bore and is arranged such that the sealing ring, which has two different axial sides, can be installed only in the correct orientation. The power tool has a piston, which is axially displaceable in a cylinder and is under spring tension. For installing the sealing ring is first thrust by hand onto the piston in the axial direction. If the orientation is wrong, this creates such strong axial forces that the piston retracts back into the cylinder counter to the spring tension, resulting in a failed installation of the sealing ring. If the sealing ring is oriented correctly, the ring is now on the piston and in contact with a radial protrusion of the cylinder. The power tool is then, by a hand motion, pressed against the tool to be equipped with the sealing ring, and a central bolt of the power tool is introduced into a centering opening of the tool. As contact pressure continues to be exerted, the radial protrusion of the now-centered cylinder pushes the sealing ring axially into the tool opening, thus completing the assembly. However, the known assembly tool is unsuitable for installing sealing rings that must be pressed at least partially radially inward into an outer annular groove of the tool to be outfitted and must therefore be deformed in a special way.
The same is true for the assembly tools known from International Patent Disclosure WO 99/07513 and U.S. Pat. No. 5,956,830. While these are both suitable for automatic sealing ring installation and can optionally be equipped with a pneumatic piston-cylinder unit, nevertheless the sealing rings can be press-fitting into suitably shaped annular grooves only in an axial direction. Radially outer annular grooves, for instance, a valve plates cannot be outfitted using the known tools.